[Determination of volatile N-nitrosamine compounds in salted aquatic products by gas chromatography-mass spectrometry].

An analytical method was developed for the determination of the extraction of volatile N-nitrosamine compounds including N-nitrosodimethylamine ( NDMA) , N-nitrosodiethylamine (NDEA), N-nitrosodipropylamine (NDPA), N-nitrosodibutylamine (NDBA), N-nitrosopiperidine (NPIP), and N-nitrosopyrrolidine (NPYR) from salted aquatic products by gas chromatography-mass spectrometry (GC-MS). In this experiment, the separation and detection conditions were optimized for different extraction methods, solid-phase extraction columns, and chromatographic columns. The results showed that the linear correlation coefficients (R2) were higher than 0.

[Determination of dichlorobromomethane in water by headspace-trap gas chromatography/mass spectrometry].

A novel method was developed for the determination of dichlorobromomethane in water using headspace-trap gas chromatography/mass spectrometry (GC/MS). Three parameters of headspace-trap including thermostatic temperature, time and cycle number were optimized by orthogonal experiment analysis. Dichlorobromomethane in water samples was analyzed under the optimized conditions of 70 degrees C and 20 minutes with the cycle number of two.

[Determination of six p-hydroxybenzoates in fruits and jams using solid-phase extraction-high performance liquid chromatography].

A method was developed for the determination of 6 p-hydroxybenzoates (methyl p-hydroxybenzoate (MHB), ethyl p-hydroxybenzoate (EHB), isopropyl p-hydroxybenzoate (IPHB), propyl p-hydroxybenzoate (PHB), isobutyl p-hydroxybenzoate (IBHB) and butyl p-hydroxybenzoate (BHB)) in fruits and jams using the combination of solid-phase extraction and high performance liquid chromatography (SPE-HPLC). Two different extraction solutions and three different mobile phases were tested for p-hydroxybenzoates analysis, and finally ethanol was used as the extraction solvent and methanol-citric acid buffer was selected as the mobile phase. The sample was extracted, and purified by an Oasis HLB solid-phase extraction cartridge, then separated on a Symmetry-C18 column and detected at the wave length of 258 nm.